Source: OHIO STATE UNIVERSITY - VET MED submitted to NRP
THE EFFECTS OF ALPHA2 ANTAGONISTS (ATIPAMEZOLE, TOLAZOLINE) AND DETOMIDINE ON RECOVERY FROM SEDATION AND ANESTHESIA IN HORSES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
ANIMAL HEALTH
Reporting Frequency
Annual
Accession No.
0201822
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Dec 15, 2003
Project End Date
Dec 14, 2004
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
OHIO STATE UNIVERSITY - VET MED
1900 COFFEY ROAD, 127L VMAB
COLUMBUS,OH 43210
Performing Department
CLINICAL SCIENCE
Non Technical Summary
Recovery from inhalant anesthesia in horses is the most perilous period of the entire anesthetic experience If low doses of alpha-2 agonists ar administered prior to the end of inhalant anesthesia, potential side effects will be detected early and appropriately treated and the sedative effects will carry into the recovery period improving the quality of recovery without significantly prolonging the duration of recovery.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
31538101180100%
Knowledge Area
315 - Animal Welfare/Well-Being and Protection;

Subject Of Investigation
3810 - Horses, ponies, and mules;

Field Of Science
1180 - Pharmacology;
Goals / Objectives
Part I: To determine the effects of the alpha2 antogonist atipamezole on horses sedated with detomidine. To determine the effects of the alpha2 antogonist tolaxoline on horses sedated with detomidine. Part II: To determine if the alpha-2 agonists detomidine and zylazine, administered 15-20 minutes before the end of inhalant anesthesia improve and reduce the incidence of complications during the recovery period. To determine if the alpha-2 agonists detomidine and xylazine, administered 15-20 minutes before the end of inhalant anesthesia significantly prolong the duration of recovery. To determine if detomidine produces a significantly better outcome than xylazine using the above administration procedures.
Project Methods
Part I: Six adult horses will be administered intravenous detomidine (0.02 mg/kg bwt) on four occasions with a minimum of seven days between administrations. 30 minutes after detoidine administration, the horse will receive one of four treatments: Group 1. IV saline as a control (10 ml); Group 2. IV atipamezole low dose (0.05 mg/kg bwt); Group 3. IV atipamezole high dose (0.1 mg/kg bwt); Group 4. IV tolazoline (4.0 mg/kg bwt). The order of treatment will be randomized and the investigators will be blinded to the treatment. Part II: One hundred and fifty (150) healthy adult horses admitted to the Ohio State University Veterinary Teaching Hospital for an elective arthroscopic surgical procedure will be randomly assigned to receive 1 ml of 0.9% saline (placebo; 50 horses), 2 ug/kg detomidine (50 horses) or 0.2 mg/kg xylazine (50 horses) 15-20 minutes before the end of inhalant anesthesia. Investigators will be blinded to the drug administered. Standard protocols for the qualitative (categorical) and quantitative (ex. number of attempts to stand; time to stand) evaluation of recovery from inhalant anesthesia will be used. Horses requiring additional sedation will receive xylazine (0.2 mg/kg, IV). Qualitative evaluations will be made by at least 3 independent evaluators and their scores averaged.

Progress 12/15/03 to 12/14/04

Outputs
Randomized, placebo-controlled double blind, descriptive study of six horses. Detomidine (0.02 mg/kg bwt i.v.) was administered to six adult horses on four separate occasions. Twenty five min later, each horse received one of four treatments: SAL- Saline (0.9% i.v.) as a placebo control; ATILOW- Atipamezole (0.05 mg/kg bwt i.v.); ATIHIGH- Atipamezole (0.1 mg/kg bwt i.v.); TOL- Tolazoline (4.0 mg/kg bwt i.v.). Sedation, muscle relaxation, and ataxia were scored by three independent observers at nine time points. Horses were led through an obstacle course at seven time points. Course completion time (sec) was recorded and the ability of the horse to traverse the course was scored by three independent observers. Horses were videotaped before, during, and after each trip through the obstacle course. Atipamezole and tolazoline administration incompletely antagonized the effects of detomidine but the time course to recovery shortened. Single bolus administration of atipamezole or tolazoline produced partial reversal of detomidine sedation.

Impacts
The ability to shorten the duration of sedation improves detomidine's safety and utility. Atipamezole or tolazoline are useful for minimizing detomidine sedation.

Publications

  • No publications reported this period